There are many ways in which Iceland can be meaningfully compared with the mantle convection-rolls model. When viewed from a holistic, bird’s-eye perspective, the pattern of the continental shelf, the mid-ocean ridges, and the position of Iceland’s stratovolcanoes together reveal a coherent geological structure. To understand this fully, it is necessary to recognize both the location and the function of the major convection rolls operating beneath Iceland. In this model, the rolls do not have fixed “axes”; instead, they sway according to their governing equations. Therefore, the true geological significance lies in the division boundaries between adjacent rolls. These boundaries, when projected through the mantle and lithosphere, naturally delimit Iceland’s volcanic zones and help explain their geometry.
Convection rolls arrangement at 64°N
Although Iceland’s brittle lithosphere is thicker than that of the surrounding oceanic crust, this is not a primary control on the island’s unusual activity. The key factor is the complex intersection zone where two long-distance convection-roll systems meet—one extending northward from equatorial regions and another extending southward from high northern latitudes. The interaction of these systems forms an overlapping polygonal pattern beneath Iceland, creating N–S and E–W patterns, such as the South Iceland Seismic Zone and the North Volcanic Zone. This convergence of roll-division boundaries generates the necessary preconditions for Iceland’s exceptional volcanic and geothermal behavior: enhanced mantle temperatures, increased melt supply, localized geothermal intensification, and mechanically weakened pathways that sustain the divergent boundary on land.
Within this framework, specific observations become clearer. Many of the best known geothermal areas closely follow the division line of the convection roll extending from the Reykjanes Ridge beneath the island. Yet they are not controlled by this single division line alone—the overlapping boundaries of other convection rolls also play a defining role. Several major geothermal zones lie precisely where these secondary roll-boundaries intersect the Reykjanes line. This is evident at Hveravellir, located where a northern roll-boundary crosses the central Icelandic system, and at Húsavík’s GeoSea geothermal field, which aligns with another such crossing point. Recent discoveries reinforce this pattern: the high-temperature system near Vaðlaheiðargöng (now supplying hot water to the Forest Lagoon by Akureyri) and the new geothermal resources near Keflavík both lie directly along intersecting convection-roll boundaries exactly as the model predicts. Other geothermal areas, such as at Grímsvötn and Kverkfjöll, are found along a parllel line, 3° east of the eastern margin of the said eastern roll of the Reykjanes Ridge convection rolls pair, also at crossings with other division lines of different depth. Such examples show that geothermal activity in Iceland is not random nor solely linked to one major upwelling line, but is instead the integrated surface expression of multiple interacting mantle-roll boundaries.
The volcanic zones can likewise be subdivided into natural segments that align with roll boundaries, and the tectonic drift vectors correspond closely with the grid formed by the convection-roll divisions. This allows a physically meaningful line to be drawn representing the true boundary between the North American and Eurasian plates—one that reflects deep-mantle dynamics rather than only surface expressions. Even the smaller peripheral volcanic zones align with the edges of adjacent polygons, occupying precisely the distances expected from secondary roll-boundary influences. In fact, all deeper rooted details of Iceland’s tectonic, geothermal, and volcanic structure can be understood by comparing it with the deep-mantle convection-roll system, which provides a unified and dynamically consistent model for interpreting the island’s geological complexity.
There is a clear and well-documented difference between the average dip of subduction zones that face east (about 27.1°) and those that face west (about 65.6°). This asymmetry has long intrigued geoscientists. Traditional explanations emphasize variations in the age and density of the subducting lithosphere—older seafloor is denser and therefore subducts at a steeper angle.
However, the Mantle Convection Rolls Model introduces an additional and complementary mechanism: the effect of Earth’s rotational velocity on the descending slab. Velocity of the subducting slab does not matter here, only the difference in rotational energy at different depths. We do not see how the tectonic plates move, but that does not mean we sould neglect the relevant calculations. In this case, calculating the difference is very simple.
Rotational Velocity and Kinetic Energy Loss
As the slab descends roughly 660 km—about one-tenth of Earth’s radius—it gradually loses rotational velocity, as the circle at surface is obviously longer then the lower circle. It therefore involves a significant kinetic-energy transfer to the surrounding mantle. If we set Earth’s radius as 1, the radius at 670 km depth is ≈ 0.9. At the equator, the difference in kinetic energy between these levels can be estimated as rotational energy at surface subtracted by rotationa energy at 670 km depth:
The result, 0.2, means that about 20% of the slab’s kinetic energy is dissipated while moving from the surface to the transition zone. Considering that the tangential velocity at the equator reaches about 1 ,674 km h⁻¹, a 20% reduction represents an immense energy transfer to the surrounding material. Imagine what happens to one cubic kilometer of slab after it loses 20% of its kinetic energy with the velocity of 1 ,674 km h⁻¹. Should it have no effect at all, or should it alter the dip of the descending slab? Of course the dip is affected by this transfer of energy, and it fits very well to the difference between the east and west of the Pacific Ocean.
The aggregate effect of this energy loss manifests differently on opposite sides of the Pacific. Along the eastern margins, the energy dissipation induces compressional pressure between converging plates; along the western margins, it produces a tensional or pulling effect. These opposing mechanical environments contribute to the observed difference in average slab dip: approximately 46° overall, with west-oriented subduction averaging near 65° and east-oriented near 27° (described in an essay by Doglioni & Panza, 2015).
Geometric Representation
This relationship can be illustrated geometrically. If the rotational velocity at Earth’s surface is represented as u = 1 and at 660 km depth as u = 0.9, two similar triangles can be drawn to represent eastward and westward subduction. The short side of each triangle—the horizontal gap between real flow (red) and the hypothetical no-rotation line (black)—corresponds to the observed angular difference. These geometric relations visually express how differential rotational velocity produces the characteristic east–west asymmetry of slab inclination. The simple drawing below shows the average difference.
Equatorial Symmetry and Mantle Roll Alignment
The same principle extends horizontally. The main division points of the equator coincide strikingly with the division boundaries of modelled lower-mantle convection rolls, which are spaced 30° apart. When subduction zones located exactly 180° apart on the equator are compared—most notably those of South America and Indonesia—their symmetry becomes evident. The position of these two trenches opposite each other can by no means be said to be just a coincidence.
This has of course been mapped in detail for each subduction zone. In turn, those subduction zones show identical, although mirrored, deviation from true north. This symmetry can be explained by referring to the mantle convection rolls model. The fact that not only position, but also deviation from north is identical can not be said to be just a coincidence.
Integration Within the Mantle Convection Rolls Model
According to the Mantle Convection Rolls Model, the slab ultimately enters a ductile, convecting mantle where geophysical conditions are balanced. The difference in slab dip between east- and west-oriented subduction zones thus arises from the rotational-kinetic interaction between the descending plate and the mantle framework through which it moves.
Horizontally moving mantle material is similarly governed by the rotating geoid, producing predictable deviations from straight-line flow that define the roll-like geometry of convection cells. The vertical and horizontal components of this system are dynamically linked—both shaped by the same rotational gradients that influence slab inclination.The Missing Correlation Between Seafloor Age and Slab Dip
If slab dip were controlled primarily by the age of the subducting seafloor, one would expect a clear correlation between older, denser lithosphere and steeper subduction angles. However, such a relationship is not observed—particularly along the western margin of the Pacific Ocean.
For example:
The Mariana Trench, one of the deepest and steepest subduction zones on Earth, indeed involves an old oceanic plate (>150 million years). But if seafloor age were the decisive factor, then all regions subducting comparably old crust should exhibit similar dip angles—which they do not.
Along the Japan Trench, the subducting Pacific Plate is also very old (130–140 million years), yet its dip is far shallower in many segments, especially near Honshu and Hokkaido, where the slab inclination decreases dramatically toward the northeast.
Conversely, some younger lithosphere—such as that near Tonga or New Britain—subducts at extremely steep angles, contradicting any simple “old plate = steep dip” rule.
In other words, no systematic correlation exists between the age of the descending seafloor and the dip angle of subduction along the western Pacific. This observation directly contradicts the density-driven model, while strongly supporting a dynamic explanation based on Earth’s rotational velocity gradients.
The striking and consistent difference between eastward- and westward-dipping slabs, on the other hand, reveals a clear global pattern that matches the expected distribution of kinetic energy within the rotating mantle.
Why Has This Explanation Been Overlooked?
It may appear surprising that such an evident physical relation—between Earth’s rotation and slab dip—has not been explicitly emphasized before. The reason may lie in the timescales involved.
When a unit volume of lithosphere, say one cubic kilometer of slab, moves downward by 100 km, it inevitably tends to drift eastward relative to the overlying surface because its rotational velocity decreases with depth. The motion is fully deterministic: the deeper the material sinks, the greater its lag relative to the surrounding mantle at that depth.
Yet this motion unfolds extremely slowly—so slowly that, within the human timeframe or even during the lifespan of an oceanic plate, the effect seems negligible. Over millions of years, however, this cumulative eastward drift becomes geophysically significant.
It alters the balance between horizontal traction and vertical descent, subtly controlling slab geometry. Because geoscientific models typically focus on instantaneous plate velocities rather than rotational energy differentials, the long-term kinematic consequences of Earth’s rotation have been largely overlooked or treated as negligible.
Thus, the explanation first formulated here appears novel not because it contradicts known physics—but because it applies fundamental physical reasoning (rotational mechanics) across a geological timescale that previous models rarely considered in full.
Conclusion
The consistent difference in dip angle between east- and west-oriented subduction zones can therefore be interpreted as a manifestation of Earth’s rotational dynamics coupled with the internal organization of mantle convection rolls. This integrated view connects global rotation, energy dissipation, and large-scale convection geometry into one coherent framework, offering an explanation that aligns observed slab asymmetry with measurable physical principles.
The geometry of subduction zones—both in terms of dip angle and global distribution—reflects the interaction between Earth’s rotation, kinetic energy dissipation, and large-scale mantle convection rolls.The absence of any correlation between seafloor age and slab dip across the western Pacific undermines the traditional density-based explanation. Instead, the consistent and global asymmetry between eastward and westward subduction aligns naturally with the physics of a rotating planet, where angular momentum and kinetic energy vary systematically with depth and latitude.What may initially appear as asymmetric behavior of tectonic plates can thus be understood as a predictable consequence of rotational mechanics acting within a viscous, convecting mantle—an effect long hidden simply because of its subtlety and timescale.
The layers of Earth allow space for a certain type of mantle convection process, called RB convection, where ‘R’ stands for Rayleigh and ‘B’ for Bénard. This type of convection should also be expected to occur within the Earth. RB convection has been studied quite intesively, and laboratory experiments with mantle material lead to the formation of convection rolls. It should be pointed out here that a section of RB convection rolls should have equal height and width.
If the RB convection rolls sections are inserted into the equatorial plane, this is the first result, as shown above. The equatorial plane has a double function, as it is both a plane of convection and rotation. When the convectional plane and rotational plane are one and the same, this simple picture emerges shown above. It fits perfectly, can be logically explained, and should therefore be studied further.
Then what happens when the rotational plane and convectional plane are separated? For us, what happens is that we have to deal with those two factors separately. The proportions, when considered from the side of physics of convection and rotation together, remain the same for different latitudes. This is shown here below:
A convection roll section is examined at latitude A and latitude B. Section A is at equator with equal height and width. B is at a higher latitude, which is shorter and the deapth is the same, so at first it seem disproportionate, but according to physics it still has the proportions of a section of equal height and width. The rotational part is not combined with the convectional part, but when comparing them and putting them together, it is obvious that the rules of RB convection apply at B in the same way as at A. We are not used to think about two separate things at one time, so we better take the trouble to take those two factors of convection and rotation and combine them graphically to be able to understand this. Thereby, we can see that RB convection is taking place at all latitudes, not only within the plane of equator.
The remaining analysis concentrates on the horizontal layout of the convection rolls. The horizontal part can be calculated, and therefore the location of the rolls of different layers is known and can be used to explain geological features all over the world.
Magic Magma 